Use of a gatran for the manufacture of a medicament of the treatment of pulmonary fibrosis

ABSTRACT

According to the invention there is provided the use of a gatran, such as inogatran or melagatran, or a pharmaceutically-acceptable derivative thereof, for the manufacture of a medicament for the treatment of pulmonary fibrosis.

[0001] This invention relates to a new use of certain low molecularweight thrombin inhibitors.

[0002] Interstitial lung disease (ILD) is a general term that includeschronic lung disorders, often characterised, initially, by inflammationof various parts of the lung, including the bronchioles, the capillariesand, particularly, the alveoli.

[0003] Such inflammation may lead to damage, in particular scarring(fibrosis) of various parts of the lung, including the alveoli and inthe interstitium, and/or regions of severe thickening of the alveolarwalls. When such scarring and/or thickening occur, a chronic stiffnessin the lungs and a decreased ability of the lung tissue to transportoxygen often results. Such histological changes in the lung tissue aretypically referred to as pulmonary fibrosis (PF).

[0004] Although the course of PF is unpredictable, patients mayexperience a variety of symptoms including dyspnea and a dry cough,which is often ignored at first. As PF progresses, dyspnea becomes amajor problem, leading to severe difficulty in performing anythingphysical, including day-to-day tasks such as walking short distances(especially up stairs), dressing and even eating. In the later stages ofdisease, patients may become less able to fight infection, may need tobreath oxygen continuously, and may experience hypoxemia, pulmonaryhypertension, cardiac failure, ischemic attack, pulmonary embolism,stroke or infection brought on by the disease, one or more of whichusually results in death.

[0005] PF may result from several known causes. These include exposureto substances that may damage/irritate the lungs, such as occupationaland/or environmental exposure to e.g. dusts and fibres (such as those ofmetals, silica and asbestos); organic matter, which may lead to anallergic reaction (e.g. Farmer's Lung); or chemicals, including certaindrugs (e.g. chemotherapeutic drugs useful in the treatment of cancer).Further, radiation therapy for e.g. breast cancer may lead to PF.

[0006] Moreover, PF may be a feature of diseases such as inter aliasarcoidosis, rheumatoid arthritis, systemic sclerosis, scleroderma,extrinsic allergic alveolitis, severe asthma, systemic granulomatosisvasculitis and adult respiratory distress syndrome (ARDS).

[0007] When the cause of PF is unknown, the disease is termed“idiopathic” PF (IPF). IPF, which is also often referred to ascryptogenic fibrosing alveolitis (CFA), is a progressive interstitiallung disease of unknown etiology. Now recognised as a distinct clinicaldisorder, IPF is characterised by a fibroproliferative response withonly minor signs of inflammation (unlike other forms of PF, brought on,for example, by other causes listed above) and almost always causesrapid fibrotic destruction of the lung (see inter alia, Am. J. Respir.Crit. Care Med., 157 1301 (1998), ibid., 161, 646 (2000), Thorax, 51,711 (1996) and N. Engl. J. Med., 341, 1264 (1999)).

[0008] Current thinking centres around IPF being triggered by anautoimmune disorder, in which the body's immune system attacks its owntissues, or by the after-effects of infection by e.g. a virus, orcigarette smoking.

[0009] The diagnosis and management of patients with IPF posessignificant challenges. Treatments for IPF include oxygen and exercisetherapies. More drastic treatments include fill lung transplantation.

[0010] Current front-line pharmaceutical treatments for IPF aim toreduce inflammation and thus arrest abnormal processes that may lead tofibrosis. Thus, at present, corticosteroids, such as prednisone, areemployed. However, perhaps in view of the fact that there is norecognisably significant inflammatory component to IPF, the degree ofsuccess of these drugs in the treatment of IPF is variable at best. Thisis in addition to the well-documented side-effects of such treatments.Other drugs, such as immunosupressants (e.g. cyclophosphamide (cytoxan),azathioprine, colchicine, methotrexate, penicillamine and cyclosporin)have been employed, though such treatments are also known to exhibitside effects, which, in some cases, can be serious.

[0011] Thus, there is a need for alternative and/or better treatmentsfor use in patients with, or at risk of, PF and especially IPF.

[0012] Gray et al (see Thorax (1999) 54, Abstract S62 and AmericanJournal of Respiratory and Critical Care Medicine (1999) 159, A73) havereported that a direct thrombin inhibitor (code name UK-156406) has theability to block collagen deposition in bleomycin-induced PF in rats.Continuous infusion of the inhibitor (0.5 mg/kg body weight/hour) via anosmotic minipump was found to reduce the stimulation of total lungcollagen of bleomycin treated animals by ca 38% after 14 days.

[0013] International patent application WO 93/11152 discloses a group ofcompounds, including HOOC—CH₂-(R)Cha-Pic-Nag-H (wherein Cha representscyclohexylalaninyl, Pic represents (S)-pipecolinic acyl and Nagrepresents noragmatino), which is also known as inogatran (see Example67 of WO 93/11152, and the list of abbreviations in that document),which are useful as thrombin inhibitors and thus as anticoagulants. Theuse of these compounds in the treatment of PF is not mentioned.

[0014] International patent application WO 94/29336 discloses a group ofcompounds that are useful as inhibitors of serine proteases, such asthrombin and/or kininogenases. The thrombin-inhibiting compounds arethus indicated as anticoagulants, and the kininogenase-inhibitingcompounds as anti-inflammatory agents. Again, PF is not mentioned.

[0015] One of the thrombin-inhibiting compounds that is specificallydisclosed in WO 94/29336 is HOOC—CH₂-(R)Cgl-Aze-Pab-H (wherein Cglrepresents cyclohexylglycinyl, Aze represents (S)-azetidine-2-carboxyl,and Pab represents para-amidinobenzylamino), which is also known asmelagatran (see Example 1 of WO 94/29336, and the list of abbreviationsin that document). International Patent Application WO 97/23499discloses prodrugs of inter alia melagatran. One of the many indicationsmentioned in WO 97/23499 is PF following treatment with radiation orchemotherapy. IPF is neither mentioned nor suggested.

[0016] We have now found that the gatrans and derivatives thereofprevent collagen deposition in the lung and may thus be used in thetreatment of PF, such as IPF.

[0017] According to a first aspect of the invention there is providedthe use of a gatran, or a pharmaceutically-acceptable derivativethereof, for the manufacture of a medicament for the treatment of PF.

[0018] Preferably, when the pharmaceutically-acceptable derivative is aprodrug of melagatran, and, more preferably, when the gatran itself ismelagatran, then the disease to be treated is IPF.

[0019] The term “PF” will be understood by those skilled in the art toinclude any condition characterised by one or more of (a) collagendeposition in the lung, (b) scarring (fibrosis) of the lung (includingthe alveoli and in the interstitium), and/or (c) regions of severethickening of the alveolar walls, one or more of which may result in achronic stiffness in the lungs and/or a decreased ability of the lungtissue to transport oxygen.

[0020] According to a second aspect of the invention there is providedthe use of a gatran, or a pharmaceutically-acceptable derivativethereof, for the manufacture of a medicament for the prevention ofcollagen deposition, and/or the treatment of a disease characterisedthereby, e.g. in the lung.

[0021] The PF may be a secondary fibrosis, which may be brought on by aninflammatory condition, such as sarcoidosis, rheumatoid arthritis,systemic sclerosis, scleroderma, extrinsic allergic alveolitis, severeasthma, systemic granulomatosis vasculitis and/or adult respiratorydistress syndrome (ARDS), or it may be IPF.

[0022] The term “IPF” will be understood to include any form of PF wherethe underlying causes of the condition are unknown and/or to include thedefinition provided in the consensus statement in Am. J Respir. Crit.Care Med., 161, 646 (2000), the relevant disclosure in which document ishereby incorporated by reference.

[0023] Particular forms of IPF that may be mentioned include inter aliadesquamative interstitial pneumonitis (DIP), acute interstitialpneumonia (AIP), non-specific interstitial pneumonia (NSIP), respiratorybronchiolitis-associated interstitial lung disease (RBILD),bronchiolitis obliterans organising pneumonia (BOOP), lymphoidinterstitital pneumonia (LIP) and, particularly, usual interstitialpneumonitis (UIP) (see, for example, Am. J. Respit. Crit. Care Med.,157, 1301 (1998)).

[0024] Treatment of PF includes therapeutic treatment as well asprophylactic treatment. By prophylactic treatment, we include prevention(inhibition) of the progress of PF in patients that have the disease.

[0025] Preferred disease states include IPF.

[0026] The term “gatran” will be understood to include inogatran andmelagatran. Preferred gatrans include inogatran.

[0027] “Pharmaceutically-acceptable derivatives” of gatrans includesalts (e.g. pharmaceutically-acceptable non-toxic organic or inorganicacid addition salts) and solvates. It will be appreciated that the termfurther includes derivatives that have the same biological functionand/or activity as the relevant gatran. Moreover, for the purposes ofthis invention, the term also includes prodrugs of the relevant gatran.The term “prodrug” includes any composition of matter that, followingoral or parenteral administration, is metabolised in vivo to form therelevant gatran in an experimentally-detectable amount, and within apredetermined time (e.g. within a dosing interval of between 6 and 24hours (i.e. once to four times daily)). For the avoidance of doubt, theterm “parenteral” administration includes all forms of administrationother than oral administration. Prodrugs of melagatran that may bementioned include those disclosed generically and specifically ininternational patent application WO 97/23499. Preferred prodrugs arethose of the formula R¹O₂C—CH₂-(R)Cgl-Aze-Pab-OH (see the list ofabbreviations in WO 97/23499 and above), wherein R¹ represents C₁₋₁₀alkyl or benzyl, such as linear or branched C₁₋₆ alkyl (e.g. C₁₋₄ alkyl,especially methyl, n-propyl, i-propyl, t-butyl and, particularly, ethyl)and the OH group replaces one of the amidino hydrogens in Pab.

[0028] Gatrans, and derivatives thereof, may be administered forsystemic delivery using appropriate means of administration that areknown to the skilled person.

[0029] Thus, in accordance with the invention, gatrans, and derivativesthereof, may be administered orally, intravenously, subcutaneously,buccally, is rectally, dermally, nasally, tracheally, bronchially,topically, by any other parenteral route, or, particularly viainhalation, especially to the lung, in the form of a pharmaceuticalpreparation comprising the active ingredient in apharmaceutically-acceptable dosage form. Depending on the disorder, andthe patient, to be treated, as well as the route of administration, thecompositions may be administered at varying doses.

[0030] Preferred modes of delivery are systemic. For the gatransthemselves, preferred modes of administration are parenteral, morepreferably intravenous, subcutaneous or by inhalation. For prodrugs ofthe gatrans, especially melagatran, preferred modes of administrationare oral, intravenous, subcutaneous or by inhalation.

[0031] In the therapeutic treatment of mammals, and especially humans,gatrans and derivatives thereof may be administered alone, but willgenerally be administered as a pharmaceutical formulation in admixturewith a pharmaceutically-acceptable adjuvant, diluent or carrier, whichmay be selected with due regard to the intended route of administrationand standard pharmaceutical practice.

[0032] Suitable formulations for use in administering inogatran andderivatives thereof are described in the literature, for example asdescribed in inter alia international patent applications WO 93/11152,WO 96/14084, WO 99/27912, WO 99/27913 and WO 00/76504, the disclosuresin which documents are hereby incorporated by reference.

[0033] Suitable formulations for use in administering melagatran andderivatives (including prodrugs) thereof are described in theliterature, for example as described in inter alia international patentapplications WO 94/29336, WO 96/14084, WO 96/16671, WO 97/23499, WO97/39770, WO 97/45138, WO 98/16252, WO 99/27912, WO 99/27913, WO00/12043 and WO 00/13671, the disclosures in which documents are herebyincorporated by reference.

[0034] Otherwise, the preparation of suitable formulations, for examplefor administration of active ingredient by inhalation, may be achievednon-inventively by the skilled person using routine techniques (see, forexample, Inhalation Aerosols: Physiological and Biological Basis forTherapy (ed. Anthony J. Hickey), Lung Biology in Health and Disease,Volume 94. Marcel Dekker Inc. (1996) and Respiratory Drug Delivery (ed.Peter R. Byron), CRC Press Inc. (1990)).

[0035] The amount of gatran or derivative in the formulation will dependon the severity of the condition, and on the patient, to be treated, aswell as the compound(s) which is/are employed, but may be determinednon-inventively by the skilled person.

[0036] According to a further aspect of the invention there is provideda pharmaceutical formulation for use in the treatment of PF comprisingan effective amount of a gatran, or a pharmaceutically-acceptablederivative thereof, in admixture with a pharmaceutically-acceptableadjuvant, diluent or carrier.

[0037] In the treatment of PF, gatrans and derivatives (includingprodrugs) thereof may also be combined with other agents known for usein the treatment of PF, for example corticosteroids, such as prednisone,immunosuppressant drugs including cyclophosphamide (cytoxan),azathioprine, colchicine, methotrexate, penicillamine, cyclosporin andinterferon gamma, and/or anti-fibrotic agents such as pirfenidone.

[0038] When gatrans, and derivatives thereof, are “combined” with othertherapeutic agents in this way, the active ingredients may beadministered together in the same formulation, or administeredseparately (simultaneously or sequentially) in different formulations.

[0039] Suitable doses of gatrans and derivatives thereof, in thetherapeutic and/or prophylactic treatment of mammalian, especiallyhuman, patients may be determined routinely by the medical practitioneror other skilled person, and include the respective doses discussed inthe prior art documents mentioned hereinbefore, the disclosures in whichdocuments are hereby incorporated by reference.

[0040] For example, suitable doses of inogatran (when inhaled) andmelagatran (when administered intravenously, subcutaneously or byinhalation), and prodrugs and derivatives of either, in the therapeuticand/or prophylactic treatment of mammalian, especially human, patientsinclude those which give a mean plasma concentration of active compoundof up to 10 μmol/L, for example in the range 0.001 to 5 μmol/L (e.g.0.01 to 1 μmol/L, such as 0.05 to 0.5 μmol/L) over the course oftreatment of the relevant condition.

[0041] In any event, the physician, or the skilled person, will be ableto determine the actual dosage which will be most suitable for anindividual patient, which is likely to vary with the condition that isto be treated, as well as the age, weight, sex and response of theparticular patient to be treated. The above-mentioned dosages areexemplary of the average case; there can, of course, be individualinstances where higher or lower dosage ranges are merited, and such arewithin the scope of this invention.

[0042] The skilled person will also appreciate that a gatran, or aderivative thereof, may be administered in an appropriate dose on an “asrequired” basis (i.e. as needed or desired).

[0043] According to a further aspect of the invention there is provideda method of preventing or treating PF, which comprises administering atherapeutically-effective amount of a gatran, or apharmaceutically-acceptable derivative thereof, to a patient in need ofsuch treatment.

[0044] The use and method described herein may have the advantage that,in the treatment of PF, and especially IPF, gatrans and derivativesthereof may not possess disadvantages of known therapies. The use andmethod described herein may also have the advantage that gatrans andderivatives thereof may be more efficacious than, be less toxic than,have a broader range of activity than, be more potent than, producefewer side effects than, be more easily absorbed than, or that they mayhave other useful pharmacological properties over, compounds known inthe prior art for the treatment of PF, such as IPF.

[0045] The invention is illustrated, but in no way limited, by thefollowing example, in which FIG. 1 shows the total collagen depositionin the lungs at the end of a bleomycin-induced lung fibrosis study forfour study groups of rats.

EXAMPLE 1 Evaluation of Inogatran in a Bleomycin-Induced Lung FibrosisModel

[0046] Forty male Sprague Dawley rats weighing 200 g were kept in cages(2 rats/cage) covered with filter tops to prevent spreading ofcarcinogenic metabolites of bleomycin. The rats had free access to foodand water.

[0047] The rats were split into four groups:

[0048] Group 1—8 rats—received 0.9% NaCl (1 mL/kg) as a control (only 6animals were ultimately used, the other 2 were used for differentpurposes).

[0049] Group 2—8 rats—received induction by way of an i.t. 2.5 mg/kg (1mL/kg) bleomycin instillation (a 15 IE injection solution (Lundbeck)).

[0050] Group 3—12 rats—received bleomycin induction as above, plus aconstant i.v. infusion of 0.9% NaCl solution (5.0 μL/h) (only 8 animalswere ultimately used, the other 4 were used for different purposes).

[0051] Group 4—12 rats—received bleomycin induction as above, plus aconstant i.v. infusion of inogatran (5 μmol/kg/h) loaded in Alzet® 2ML2pumps at a concentration of 200 μmol/mL (88 mg/mL) in 0.9% NaCl (only 8animals were ultimately used, the other 4 were used for differentpurposes).

[0052] The rats were anaesthetised by way of an i.p. injection (2 mL/kg)of Ketalar™ (50 mg/mL ketamin; Parke-Davis)/Rompun.vet™ (20 mg/mLxylazin; Bayer) (1.75 mL/0.35 mL). A pre-filled minipump connected to aPE60 catheter was inserted into the jugularis vein. A s.c. pocket wascreated on the back of the animal. The pump was led into this pocket.The incision on the neck was closed with wound clips.

[0053] The pre-filled pump with catheter was incubated in 37° C. 0.9%NaCl overnight before implantation to enable immediate pumping aftersurgery. This was to avoid clotting in the catheter.

[0054] Plasma and bronchiolar lavage fluid (BAL) were collected fromfour rats in groups 3 and 4, and from two rats in group 1, six daysafter induction, for quantification of plasma concentration of compoundand thrombin activity in BAL.

[0055] After 14 days, all rats received an overdose of pentobarbital(i.p.). The rats were weighed and the lung was dissected and weighed.One lobe was placed in Histofix™ (buffered 5% formaldehyde solution) forhistological examination. The remaining lungs were snap frozen in liquidnitrogen and stored prior to analysis at −70° C.

[0056] The following parameters were measured:

[0057] Body weight (body weight gained during the experiment).

[0058] Lung weight (total lung wet-weight).

[0059] Total collagen (quantification of hydroxyproline according to theprocedure described in Stegemann-Stadler et al, Determinations ofHydroxyproline, Clin. Chim. Acta (1967) 18, 267-273).

[0060] BAL (thrombin activity in BAL on day 6).

[0061] Concentration of inogatran in plasma on day 6.

[0062] The analysis of inogatran plasma on day 6 after implantationindicated that the pumps delivered the compound. Untreated rats (2) andrats receiving vehicle from the pump (4) had undetectable levels ofinogatran in plasma, while the rats receiving compound had a plasmaconcentration in the range 2 to 7 μmol/L (approximately).

[0063] Rats instilled with bleomycin shows a significantly slower bodyweight gain (BWG) compared to the controls.

[0064] Bleomycin instillation resulted in a significant increase intotal lung weight from approximately 1.5-2.5 g/lung in all groups.Inogatran (4-5 μmol/kg/hr) showed no effect on total lung weight(wet-weight).

[0065] Analysis of hydroxyproline content (μg/mL tissue) in the lungsshowed a two-fold increase in the bleomycin group compared to normalcontrols (2.59±0.27 μg/mg tissue, compared to 1.31±0.27 μg/mg tissue,see also FIG. 1). Inogatran treatment showed an almost completeinhibition of this collagen deposition (1.37±0.10 μg/mg tissue, comparedto its control value of 2.34±0.14 μg/mg tissue, P=0.0008) at day 14.

[0066] In summary, this study showed expected changes in body weight,lung weight and hydroxyproline content in the bleomycin control comparedto normal rats. However, there was almost complete inhibition ofcollagen deposition as a result of treatment with inogatran (cf. Gray etal supra).

[0067] These data demonstrate the potential utility of gatran compoundsin the treatment of PF.

1. The use of a gatran, or a pharmaceutically-acceptable derivativethereof, for the manufacture of a medicament for the treatment ofpulmonary fibrosis.
 2. The use of a gatran, or apharmaceutically-acceptable derivative thereof, for the manufacture of amedicament for the prevention of collagen deposition in the lung.
 3. Amethod of treatment of pulmonary fibrosis, which comprises administeringa therapeutically effective amount of a gatran, or apharmaceutically-acceptable derivative thereof, to a patient in need ofsuch treatment.
 4. A pharmaceutical formulation for use in the treatmentof pulmonary fibrosis, which formulation comprises an effective amountof a gatran, or a pharmaceutically-acceptable derivative thereof.
 5. Useof a gatran, or a pharmaceutically-acceptable derivative thereof, forthe treatment of pulmonary fibrosis, by administering a gatran, or apharmaceutically-acceptable derivative thereof, to a patient.
 6. The useof a gatran, or a pharmaceutically-acceptable derivative thereof, in thetreatment of pulmonary fibrosis.
 7. Use, method or formulation asclaimed in any one of claims 1 to 6 (as appropriate), wherein the gatranis inogatran.
 8. Use, method or formulation as claimed in any one ofclaims 1 to 6 (as appropriate), wherein the gatran is melagatran. 9.Use, method or formulation as claimed in claim 8, wherein the derivativeof melagatran is a prodrug of melagatran.
 10. Use, method or formulationas claimed in claim 9, wherein the prodrug is of the formulaR¹O₂C—CH₂-(R)Cgl-Aze-Pab-OH, wherein R¹ represents linear or branchedC₁₋₆ alkyl and the OH group replaces one of the amidino hydrogens inPab.
 11. Use, method or formulation as claimed in claim 10, wherein R¹represents methyl, ethyl, n-propyl, i-propyl or t-butyl.
 12. Use, methodor formulation as claimed in any one of claims 1 or 3 to 11, wherein thepulmonary fibrosis is a secondary fibrosis.
 13. Use, method orformulation as claimed in claim 12, wherein the fibrosis is brought onby an inflammatory condition.
 14. Use, method or formulation as claimedin claim 13, wherein the condition is sarcoidosis, rheumatoid arthritis,systemic sclerosis, scleroderma, extrinsic allergic alveolitis, severeasthma, systemic granulomatosis vasculitis or adult respiratory distresssyndrome.
 15. Use, method or formulation as claimed in any one of claims1 or 3 to 11, wherein the pulmonary fibrosis is idiopathic pulmonaryfibrosis.